Rotor for a rotary electric machine

Abstract

Rotor (30) for a rotary electric machine, comprising: - at least one permanent magnet (1), - a rotor mass (33) comprising laminations stacked on top of one another, comprising at least one housing (4) accommodating the permanent magnet (1), the housing (4) being delimited by at least one large face (5a) facing a long side (2a) of the permanent magnet (1), at least one lamination (6) comprising at least two cutouts (10) between them creating at least one tab (12) meeting said large face (5a) of the housing (4) and extending into the housing (4), notably in the direction of the air gap, the lamination (6) comprising one or more punchings (15) formed in the tab or tabs (12) and enabling the permanent magnet (1) to be held against an opposite face (6b) of the housing (4).

Description

[0001] Description

[0002] Title: Rotor of a rotating electric machine

[0003] The present invention claims priority from French application 2202832 filed on March 29, 2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0004] Technical field

[0005] The present invention relates to rotating electrical machines and more particularly to the rotors of such machines. The invention relates to rotors with permanent magnets.

[0006] The invention relates more particularly to synchronous or asynchronous alternating current machines. It relates in particular to traction or propulsion machines for electric (Battery Electric Vehicle) and / or hybrid (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle) motor vehicles, such as private cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval, aeronautical or wind power applications.

[0007] Prior art

[0008] Permanent magnet rotors are generally composed of a rotor mass and permanent magnets of various geometric shapes.

[0009] The rotor mass may consist of a stack of thin cut magnetic laminations. It may consist of one or more stacks of laminations stacked on top of each other.

[0010] The permanent magnets can be arranged on the surface, directly facing the air gap or, alternatively, be arranged inside the rotor mass, in housings thereof, then being called "buried" or "embedded".

[0011] In this case, it is necessary to ensure radial and / or axial mechanical locking of the permanent magnets in their housing, this locking must be sufficient to avoid damage to the permanent magnets and allow the proper functioning of the rotating electrical machine. Indeed, in the event of insufficient wedging, the permanent magnets can be subjected to micro-displacements, which can lead to their destruction, to a degradation of the electrical and magnetic performance of the machine and to a lack of balancing.

[0012] To fix the magnet in its housing, several techniques are currently applied, such as the use of claws, wedge(s), glue, a specific shape of magnet and corresponding housing, for example the use of magnets having a trapezoidal cross-section, or even the impregnation of the magnet in its housing after its installation.

[0013] However, these techniques have certain drawbacks. Their implementation can be tricky and expensive.

[0014] Using an intermediate part such as a shim involves additional cost and can complicate the manufacturing process.

[0015] The use of claws is not suitable for certain types of permanent magnets which could suffer from scratches.

[0016] Gluing magnets into their housings is a lengthy process that generally requires a heating operation followed by a cooling operation. Gluing magnets can also cause drips, which impacts the cleanliness of the parts and makes machine manufacturing more complex. In addition, gluing magnets involves a risk of positioning dispersion between the different magnets for the same sheet metal stack, but also from one sheet metal stack to another if no pre-holding of the magnets is put in place before the gluing step. Finally, gluing can pose a problem of durability over time of the assembly for certain applications, and makes retrieving the magnets practically impossible without deterioration.

[0017] As for impregnation, it is a long, expensive and cumbersome process in terms of implementation, given the need to use varnish tanks and ovens. In addition, it imposes a thermal constraint linked to the demagnetization of the magnets and also makes the recovery of the magnets impossible without deterioration.

[0018] Furthermore, in order to improve the cost and performance of electrical machines, it may be necessary to increase the quantity of magnets, especially when it is not possible to improve their quality, or to maintain the same performance with lower quality and less expensive magnets. Optimal electromagnetic performance is obtained when a buried magnet - which has in cross-section two opposite short sides and two opposite long sides - is in perfect contact on one or both of its opposite long sides with the lamination pack in which it is buried, the passage of the magnetic flux from the magnets to the lamination pack being maximized.

[0019] However, there is generally a clearance between the magnets and their housings in the sheet metal pack in which they are inserted, thus constituting an air gap from the magnetic point of view which necessarily induces losses in the electromagnetic performance of the machine. Such a clearance is linked to manufacturing constraints which do not allow, at reasonable costs, to respect very precise dimensions in the cutting of the sheets or in the design of the magnets. A clearance can also be due to the fact that, since the magnets are sensitive to corrosion, it may be necessary to cover them with a protective coating which also induces uncertainty in their dimensions.

[0020] Furthermore, assembly constraints require maintaining a certain clearance between the magnets and the housings of the sheet metal pack, so as to facilitate the insertion of the magnets into the latter, in particular when the sheet metal pack is formed from a stack of thin magnetic sheets. Indeed, in this case, the walls of the sheet metal pack may not be perfectly straight given the fact that they are made from a stack of thin sheets, which may require an even greater assembly clearance.

[0021] If the machine has several magnets arranged in several rows per pole in the sheet metal stack, the clearances of the magnets in the different rows add up and weaken the magnetic performance of the machine accordingly.

[0022] Furthermore, the use of foldable tabs can lead to a risk of the tab initiating breakage and breaking.

[0023] In international application WO 2022 / 029053, the permanent magnets are locked by foldable tabs.

[0024] International application WO 2022 / 029058 relates to a rotor in which the magnets are blocked by two punches.

[0025] In application EP 3 890 162, the sheets comprise protrusions and openings arranged near the protrusions in order to allow the deformation of bridges of material extending between the protrusions and the openings, to block the permanent magnets. There are no punchings within the meaning of the invention. In application US 2021 / 0028662, certain sheets comprise blockers of non-symmetrical triangular general shape, which are positioned on the sides of the permanent magnets to block them. These blockers are not punchings within the meaning of the invention.

[0026] In applications DE 10 2017 210879, EP 3 611 824 and EP 3 695 486, the magnets are held by tabs. There is no punching.

[0027] In DE 10 2020 102457, the sheets have openings to allow the deformation of material bridges extending above the openings, to block the permanent magnets. There are no punchings within the meaning of the invention.

[0028] Finally, in JP 2012 244677, an elastic body is used, placed in a groove in the sheets.

[0029] There is a need to improve magnetic performance and reduce manufacturing and assembly costs of rotating electrical machines.

[0030] Summary of the invention

[0031] The invention aims to meet this need and thus has as its subject, according to one of its aspects, a rotor of a rotating electrical machine, comprising:

[0032] - at least one permanent magnet having in cross-section, perpendicular to an axis of rotation of the rotor, at least one large side and at least one small side,

[0033] - a rotor mass comprising sheets stacked on top of each other, the rotor mass comprising at least one housing receiving the permanent magnet, the housing being delimited by at least one large face opposite a large side of the permanent magnet, at least one sheet comprising at least two cutouts forming between them at least one tab connecting to said large face of the housing and extending into the housing, in particular in the direction of the air gap, the sheet comprising one or more punchings made in the tab(s) and making it possible to hold the permanent magnet against an opposite face of the housing.

[0034] By "punching" is meant a deformation of the sheet metal, which is convex towards the inside of the housing, in particular on a large face of the housing. This is a local deformation of the sheet metal oriented in the housing. The punching(s) can make it possible to hold the permanent magnet against the opposite face of the housing. The punching within the meaning of the invention is not through, it is different from an opening in the sheet metal. The quantity of material displaced is thus less, which makes it easier to move it. The orientation of the material movement is also more precise.

[0035] When the face of the housing has two punches convex towards the inside of the housing, the punches can be positioned on the face of the housing so as to be opposite respectively the first and second third of the large side of the magnet.

[0036] When moving parallel to the permanent magnet at a punch, one may encounter a free space created by the cutout(s).

[0037] The leg(s) within the meaning of the invention are not deformable, they do not bend, and they may in particular not deform outside the plane of the sheet metal when the permanent magnets are inserted into the rotor mass. The leg(s) may be configured so as not to be deformed outside the plane of the sheet metal when the rotor rotates.

[0038] The leg(s) may not be in contact with the corresponding permanent magnet before punching. Before punching, there may be clearance between the leg(s) and the permanent magnet.

[0039] Each leg may have a punch, including a single punch. The punch may be centered on the leg, including centered between the two cutouts that provide the leg.

[0040] The leg(s) can be in one piece with the rest of the sheet metal.

[0041] The cutouts facilitate and delimit the deformation of the sheet metal due to punching and orient it, promoting radial deformation, in particular the deformation of the sheet metal towards the inside of the corresponding housing. In addition, material creep due to punching is facilitated. This results in improved blocking of the permanent magnets.

[0042] The invention provides better clamping of the permanent magnet for a given punching depth. The invention can also allow for a greater gap to be filled between the face of the housing and the permanent magnet. The punching force can also be lower for a given clamping of the permanent magnet, which can reduce the number of punches to be carried out and thus the capacity of the punching press.

[0043] When the rotor is viewed along an X axis of rotation, the tab(s) may not be superimposed with a permanent magnet, unlike a tab, in particular a deformable tab intended to deform when the permanent magnet is inserted.

[0044] When the rotor mass comprises one or more sheets without cutouts and tabs, the tab(s) may be superimposed with such a sheet. In other words, the tab may not protrude from a sheet without tabs and cutouts within the meaning of the invention, unlike a tab, in particular a deformable tab intended to deform when the permanent magnet is inserted.

[0045] Alternatively, the tab may protrude from a sheet metal without a tab, and be received in a groove provided in the corresponding permanent magnet.

[0046] The presence of the tab, cutouts and punching eliminates the need for glue. It can also be used as a complement to gluing, allowing the magnet to be positioned before gluing. It can minimize, on the one hand, micro-movements of the permanent magnet in the housing and therefore the risk of cracking the permanent magnet, and on the other hand, vibrations of the permanent magnet in the housing and therefore noise.

[0047] Statement of the invention

[0048] Legs and cutouts

[0049] The leg(s) may be symmetrical in shape with respect to an axis of symmetry, in particular an axis of elongation of the leg. The symmetry of the leg allows better control of its deformation during punching.

[0050] The cutout can have any shape, for example a rounded or non-rounded shape, a shape with angles, in particular a square, rectangular, triangular shape, or correspond to a longitudinal notch.

[0051] The cutout may in particular be symmetrical with respect to an axis of symmetry, in particular an axis of elongation of the cutout. A cutout may have a width depending on its length. A ratio of the width 1 of a cutout to its length L may be between 1 and 2, better between 1.1 and 1.9 or even between 1.2 and 1.8, or even between 1.3 and 1.7, being for example of the order of 1.5.

[0052] The bottom of a cutout can have a rounded shape, for example an arc of a circle. The radius of curvature can, for example, be of the order of the thickness e of the corresponding sheet metal. The radius of curvature can be greater than or equal to 0.3 mm. For example, in the case of a sheet metal with a thickness of 0.35 mm, the radius of curvature can be 0.35 mm.

[0053] In one embodiment, the cutout(s) may have a general V-shape, with a rounded bottom. The rounding may have a radius of curvature of between 0.1 and 2 mm, better still between 0.2 and 1 mm, or even between 0.3 and 0.4 mm, for example being 0.35 mm.

[0054] The leg(s) may have a flattened area at their free end. Alternatively, the leg(s) may have a rounded shape at their free end.

[0055] A distance d between the edge of the tab, in particular at the level of the flat area, and the edge of the punching, can be between 0.3 and 0.7 mm, better between 0.4 and 0.6 mm, being for example of the order of 0.5 mm.

[0056] A half-width B of a tab, corresponding to the distance between the center of the tab and the edge of the cutout, can be greater than a radius R of the punching added to 1.5 times the thickness e of the sheet. We can write: B > R + 1.5 e.

[0057] The half-width B of a tab may be between 0.8 and 2.5 mm, better between 1.0 and 2.0 mm, being for example of the order of 1.5 mm. The width of a tab may be between 1.8 mm and 5 mm, better between 2 mm and 4.05 mm, being for example of the order of 3 mm or 2.55 mm.

[0058] An angle C between the parallel to the edge of the flat part of the tab passing through the center of the punching and the tangent to the bottom of the cutout passing through the center of the punching may be greater than or equal to 0°. The angle C may be between 0° and 90°, better between 10° and 50°, or even between 20° and 40°, being for example of the order of 30°.

[0059] The leg(s) may be positioned in the center of a face of the corresponding housing, in particular in the center of a large face of the corresponding housing.

[0060] Side housings may have a single tab. Side permanent magnets may be held with a single punch. The center housing of a row of housings may have a single tab. The middle permanent magnet of the row may be held with a single punch.

[0061] Alternatively, a housing face may have two legs, which may in this case be located approximately one-third to two-thirds of the length of the housing face.

[0062] Alternatively, one face of a housing may have three legs.

[0063] In one embodiment, the central housing of a housing row may have two legs. The two legs may be separated by a cutout that is larger than the side cutouts. The permanent magnet in the middle of the row is thus held with two punches, which improves its retention and adapts to the positioning of the magnet, while minimizing magnetic impact.

[0064] Furthermore, the sheet metal may include one or more punchings made in a short side of a housing, in particular a central housing and / or a lateral housing. Thus, the corresponding permanent magnet may be blocked by two punchings, one being positioned on the long side of the magnet and the other on the short side of the magnet. For example, punching at least one of the short sides of the central magnet makes it possible to repeatably systematically press the magnet on the same side and therefore to reduce the variation in unbalances generated by the uncertainty in positioning the magnets.

[0065] Groove

[0066] At least one permanent magnet may comprise a groove, in particular along its entire length, intended to receive one or more metal tabs of the rotor mass. In this configuration, the cutouts are provided on either side of the tab over the entire or almost the entire length of the housing, and the tab protrudes from a large face of the housing. The groove may in particular be provided on a large side of the permanent magnet, in particular opposite the air gap. The groove of the permanent magnet extends longitudinally, parallel to an axis of rotation of the rotor.

[0067] This configuration is advantageous in that the punching provided in the tab can allow the permanent magnet to be held in three different directions, namely a first direction pushing the permanent magnet towards the air gap, and furthermore two directions perpendicular to the first direction, with possible deformation of the tab on three sides thereof. There is no deformation or bending of the tab when inserting the corresponding permanent magnet, and there can remain a clearance between the tab and the permanent magnet in the groove thereof before punching.

[0068] During punching, the material of the tab is deformed around the punching, which can fill the gap between the tab and the permanent magnet, and immobilize the magnet.

[0069] Permanent magnets

[0070] The cross-section of a permanent magnet is perpendicular to an axis of rotation of the rotor.

[0071] The permanent magnet may have in cross section a first short side and a second short side, opposite the first. The permanent magnet may have in cross section a first long side and a second long side, opposite the first.

[0072] Permanent magnets may have a generally rectangular cross-section. In particular, they may not have a generally trapezoidal cross-section. Such a shape may be more standard and therefore less expensive.

[0073] The rotor may have buried permanent magnets. The permanent magnets may not be arranged circumferentially. They may not be arranged on the surface of the rotor mass.

[0074] The rotor mass may comprise permanent magnets arranged obliquely to the air gap. Alternatively, the rotor mass may comprise permanent magnets arranged tangentially to the air gap.

[0075] They can be arranged in one or more rows, including a U or V shape. Permanent magnets can be arranged in one, two, or three or more rows.

[0076] In one embodiment, the housings of a pole may be arranged in a first and second row of housings, the second row may be closer to the air gap than the first row. The first row of housings may have three housings arranged in a U-shape, with a center housing and two side housings. The housings of the second row may be arranged in a V-shape.

[0077] Each housing of the sheet metal may have one or two legs. In one embodiment, each housing forming the side branches of a U or a V may have a single leg. Each housing forming the bottom of a U may have one or two legs. The rotor may have permanent magnets arranged to form poles of the rotor. The cutouts and / or punchings of a pole of the rotor may be arranged symmetrically with respect to each other.

[0078] Permanent magnets can be coated with a coating material, which can be advantageously ductile. A ductile coating can ensure good magnet retention and avoid pollution from chips, dust, or other residues, which would be a disadvantage in a liquid-cooled machine, for example.

[0079] Tabs

[0080] At least one sheet may include at least one deformable tab.

[0081] The tab can connect to a large face of the housing, for example between two legs.

[0082] The housing being delimited by at least one large face opposite a large side of the permanent magnet, at least one sheet may comprise at least one tab connecting to a large face of the housing and extending into the housing, in particular in the direction of the air gap, the tab(s) making it possible to hold the permanent magnet against an opposite face of the housing.

[0083] The tab helps to ensure the permanent magnet is correctly positioned.

[0084] In the case where the sheet metal has such a tab, it may be advantageous for the sheet metal to have two tabs, one on each side of the tab.

[0085] Alternatively or additionally, the tab may connect to a small face of the housing and extend into the housing, in particular towards the air gap, the tab(s) making it possible to hold the permanent magnet against an opposite face of the housing.

[0086] The said small face is opposite a small side of the permanent magnet.

[0087] The tab(s) have a slight overlap with the corresponding permanent magnet, which allows for a slight deformation of the tab when inserting the permanent magnet into its housing, and a jamming of the latter by compression. The tab(s) are deformable, and can deform outside the plane of the sheet metal when inserting the permanent magnets into the rotor mass. The tab(s) can be configured to be deformed outside the plane of the sheet metal so as to press against the short side of the permanent magnet. The tab(s) may not bend completely when inserting the corresponding permanent magnet. On the other hand, the tabs can deform outside the plane of the rotor mass sheet metal when inserting the corresponding permanent magnet.

[0088] The tab(s) may be configured to push the permanent magnets toward the air gap. The tab(s) may be configured to push the permanent magnets toward the outer diameter of the rotor. Such a push is advantageously the same as that caused by the effect of centrifugal force on the permanent magnets. The tabs may not be configured to push the permanent magnets toward the axis of rotation of the rotor. In particular, the tabs may not be oriented toward the inside of the rotor, but rather toward the outside thereof.

[0089] The tab can be used to mechanically lock the permanent magnet in the housing during its insertion into the housing and / or during operation of the machine when the permanent magnet is in place in the housing. The tab can thus be used to pre-position and / or maintain the permanent magnet in the housing, in particular during operation of the machine.

[0090] The permanent magnet having in cross section a first small side and a second small side, opposite the first, the tab can be configured to press against the first small side of the permanent magnet, at least one sheet comprising at least one stop opposite the second small side of the permanent magnet.

[0091] Sheet metal

[0092] In one embodiment, all the laminations of the rotor mass have cutouts and tabs within the meaning of the invention. All the laminations of the rotor mass may be identical to each other.

[0093] Alternatively, the rotor may also comprise laminations without cutouts and tabs. The laminations provided with cutouts and tabs within the meaning of the invention may in particular be arranged at one or both axial ends of the rotor mass. The laminations without cutouts and tabs may be arranged in the middle of the rotor mass, between two sets of laminations provided with cutouts and tabs within the meaning of the invention. The laminations with cutouts and tabs may be arranged at each end of the rotor lamination stacks. This ensures good retention by punching of the magnets in each rotor lamination stack. A rotor mass may in particular comprise 5 to 30% of laminations comprising cutouts and tabs within the meaning of the invention. The rotor mass may comprise, for example, at least two laminations comprising cutouts and tabs, in particular three, four or five laminations comprising cutouts and tabs.

[0094] A single sheet of the rotor mass may comprise several cutouts and tabs, each tab being in particular formed in said sheet and being in particular in a single piece with the rest of said sheet. Said sheet may comprise several housings and one or two tabs per housing. The rotor mass may then comprise, on the one hand, sheets comprising several housings and one or two tabs per housing or for certain housings, and on the other hand, sheets without tabs and cutouts.

[0095] The sheets may have a recess that extends from the side housing toward the center housing. The recess may be configured to project radially from the center housing. The recess may have an edge that extends at least partially parallel to an edge of the center housing.

[0096] Machine

[0097] The invention also relates to a rotating electrical machine, comprising a stator and a rotor as defined above.

[0098] The machine can be used as a motor or as a generator. The machine can be reluctance. It can be a synchronous motor or, alternatively, a synchronous generator. Alternatively, it can be an asynchronous machine.

[0099] The maximum rotation speed of the machine may be high, for example, greater than 10,000 rpm, better still greater than 12,000 rpm, for example, in the order of 14,000 rpm to 15,000 rpm, or even 20,000 rpm or 24,000 rpm or 25,000 rpm. The maximum rotation speed of the machine may be less than 100,000 rpm, or even 60,000 rpm, or even less than 40,000 rpm, better still less than 30,000 rpm.

[0100] The invention may be particularly suitable for high-power machines.

[0101] The machine may have a single inner rotor or, alternatively, an inner rotor and an outer rotor, arranged radially on either side of the stator and coupled in rotation. The machine may be inserted alone in a housing or inserted in a gearbox housing. In this case, it is inserted in a housing which also houses a gearbox.

[0102] The machine has a stator. The stator has teeth defining notches between them. The stator may have electrical conductors, at least some of the electrical conductors, or even a majority of the electrical conductors, which may be U-shaped or I-shaped.

[0103] Manufacturing processes

[0104] The invention also relates to a method for manufacturing a rotor of a rotating electrical machine as defined above. The method may comprise the step of introducing longitudinally, along the axis of rotation of the rotor, at least one permanent magnet into the housing.

[0105] The invention also relates, independently or in combination with the above, to a method of manufacturing a rotor of a rotating electrical machine, comprising the following steps:

[0106] (a) provide a rotor mass of the rotor comprising housings in which one or more lugs extend, each formed between two cutouts,

[0107] (b) inserting permanent magnets into the rotor mass housings of the rotor, the legs not undergoing any deformation during this insertion, and

[0108] (c) making one or more punches in the leg(s) so as to hold the permanent magnet against an opposite face of the housing.

[0109] The permanent magnet can be introduced magnetized or unmagnetized into the housing, along the axis of rotation of the rotor.

[0110] Punching can be carried out using a punch, the shape of which can be chosen from the following list, which is not exhaustive: cylindrical, sharp-edged or spherical, half-cylinder with the cylindrical part oriented towards the housing side. A cylindrical shape advantageously makes it possible to avoid having to orient the punch. A spherical cylindrical shape can allow less material to be moved than a cylindrical shape with a sharp edge, with constant depression.

[0111] The punching depth can be between 0.5 and 3 mm, better between 0.75 and 2 mm, being for example of the order of 1 mm. The punching depth can for example depend on the thickness of the sheet metal. It is the displacement of the sheet material by the punch, creating the punching, which allows the permanent magnet to be held. The orientation of the displacement of the sheet material can be favored by the cutouts located on either side of the tab.

[0112] The tabs are present in the housings before the permanent magnets are inserted into them. The tabs are not formed after the permanent magnets are inserted into the rotor mass.

[0113] The permanent magnets can be inserted longitudinally, along the rotor's axis of rotation, into the corresponding housings.

[0114] In the case where the rotor mass comprises several stacks of laminations stacked on top of each other, the method may first comprise the step of longitudinally introducing at least one permanent magnet into the housing of each stack of laminations, then the step of stacking the stacks of laminations on top of each other, with the permanent magnets in the housings.

[0115] Brief description of the drawings

[0116] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its implementation, and by examining the attached drawing, in which:

[0117] [Fig 1] Figure 1 is a schematic and partial view, in cross-section, of an example of a rotor of a rotating electrical machine according to the invention.

[0118] [Fig 2] Figure 2 is a detail view.

[0119] [Fig 3] Figure 3 is a detailed view.

[0120] [Fig 4] Figure 4 is a detailed perspective view.

[0121] [Fig 5] Figure 5 is a view of two laminations of the rotor of Figures 1 to 4.

[0122] [Fig 6] Figure 6 is a view of two laminations of the rotor of Figures 1 to 4, with the permanent magnets.

[0123] [Fig 7] Figure 7 is a schematic and partial cross-sectional view of an alternative embodiment.

[0124] [Fig 8a] Figure 8a is a schematic and partial cross-sectional view of an alternative embodiment.

[0125] [Fig 8b] Figure 8b is a detail view. [Fig 8c] Figure 8c is a view of a sheet of the rotor of Figures 8a and 8b, with the permanent magnets.

[0126] [Fig 8d] Figure 8d is a detailed perspective view.

[0127] [Fig 8e] Figure 8e is a schematic and partial perspective view of the rotor of Figures 8a to 8d.

[0128] Detailed description

[0129] Figures 1 to 6 illustrate an example of a rotor 30 of a rotating electrical machine according to the invention, comprising a rotor mass 33 comprising sheets 6 stacked on top of each other and in which housings 4 are provided. Permanent magnets 1 are inserted into each of the housings 4.

[0130] The magnets 1 are in this example of generally rectangular shape in cross-section, as illustrated in Figure 1. Each magnet 1 has, in cross-section, on the one hand, a first large side 2a and a second large side 2b, opposite the first, and on the other hand, a first small side 3a and a second small side 3b, opposite the first. Each housing 4 is delimited by two faces 5a, 5b facing respectively the first large side 2a and the second large side 2b of the magnet 1, as well as by two faces 6a, 6b facing respectively the first small side 3a and the second small side 3b of the magnet 1.

[0131] According to the invention, at least one sheet 6 comprises cutouts 10, two cutouts 10 forming between them a tab 12 connecting to said large face 5a of the housing 4 and extending into the housing 4 in the direction of the air gap, as for example visible in FIG. 2.

[0132] The sheet 6 further comprises a punching 15 formed in a tab 12 and making it possible to hold the permanent magnet 1 against an opposite face 5b of the housing 4. The tab(s) 12 are in this example of symmetrical shape with respect to an axis of symmetry, which is an axis of elongation of the tab 12.

[0133] As illustrated in Figure 3, the cutout 10 has a general V-shape, with an opening angle a of approximately 20°, and with a rounded bottom in an arc of a circle. The rounding has a radius of curvature of the order of 0.30 mm or 0.35 mm.

[0134] Furthermore, the cutout is here symmetrical with respect to an axis of symmetry, which is an axis of elongation of the cutout. A ratio of the width 1 of the cutout 10 to its length L may be between 1 and 2, being for example of the order of 1.5. The tab 12 has a flat area at its free end. A distance d between the edge of the tab 12 at the level of the flat area and the edge of the punching 15 is for example of the order of 0.5 mm.

[0135] A half-width B of a tab 12, corresponding to the distance between the center of the tab 12 and the edge of the cutout 10, may be greater than a radius R of the punching 15 plus 1.5 times the thickness e of the sheet 6. We can write: B > R + 1.5 e. The half-width B of a tab 12 is for example of the order of 1.5 mm.

[0136] An angle C between the parallel to the edge of the flat surface of the tab 12, passing through the center of the punching 15, and the tangent to the bottom of the cutout 10 passing through the center of the punching 15 can be of the order of 30°.

[0137] In the illustrated example, the rotor comprises permanent magnets 1 arranged to form poles of the rotor, the cutouts 10 and the punchings 15 of a pole of the rotor being arranged symmetrically with respect to each other.

[0138] More precisely, the rotor comprises permanent magnets 1 arranged in two rows, one in a U shape and the other in a V shape. In this embodiment, each housing forming the lateral branches of a U or a V has a single leg 12, and each housing forming the bottom of a U has two legs 12.

[0139] As illustrated in Figure 2, the tab 12 is positioned in the center of a face of the corresponding housing 4, in particular in the center of a large face 5a of the housing 4.

[0140] The side housings having a single leg, the side permanent magnets are held with a single punching 15. The central housing of a row of housings having two legs, the permanent magnet in the middle of the row is thus held with two punchings 15. In addition, the two legs, which in this case can be located at approximately one third and two thirds of the length of the face of the housing, are separated by a cutout 10 wider than the side cutouts.

[0141] Alternatively, as illustrated in Figure 7, the central housing of a housing row may have a single tab 12. The permanent magnet in the middle of the U-shaped row is here held with a single punching 15.

[0142] In another embodiment variant illustrated in Figures 8a to 8e, the permanent magnets 1 each comprise a groove 20, in particular over their entire length, said groove 20 being intended to receive a tab of the laminations 6 of the rotor mass. In this configuration, the cutouts 10 are provided on either side of the tab 12 over all or almost all of the length of the housing, and the tab protrudes from a large face 5a of the housing. The groove 20 is in particular provided on a large side 2a of the permanent magnet, opposite the air gap, as visible in Figure 8a. The groove 20 of the permanent magnet extends longitudinally, parallel to an axis of rotation of the rotor, as visible in Figures 8d and 8e.

[0143] The punching 15 provided in the tab 12 makes it possible to hold the permanent magnet in three different directions, namely a first direction pushing the permanent magnet towards the air gap, and furthermore two directions perpendicular to the first direction, with possible deformation of the tab on three sides thereof, as illustrated in figure 8b.

[0144] There is no deformation or bending of the tab when inserting the corresponding permanent magnet, and there may be some clearance between the tab and the permanent magnet in the permanent magnet groove. During punching, the material of the tab is deformed around the punching, which can fill the existing clearance between the tab and the permanent magnet, and immobilize the magnet.

[0145] Furthermore, in the example described with reference to figures 1 to 6, at least one sheet 6 of the rotor comprises deformable tabs 7.

[0146] A deformable tab 7 connects to a large face 5a of the central housing, between the two tabs 12 thereof. 11. The tab 7 extends into the housing 4 in the direction of the air gap, the tab(s) 7 making it possible to hold the permanent magnet 1 against the opposite face 5b of the housing 4. In the case where the sheet metal comprises such a tab, it may be advantageous for the sheet metal to comprise two tabs 12, one on each side of the tab.

[0147] Furthermore, a deformable tab 7 connects to a small face 6a of the housing 4 and extends into the housing 4 towards the air gap. This tab 7 makes it possible to hold the permanent magnet 1 against the opposite face 6b of the housing 4, opposite a small side of the permanent magnet.

[0148] The sheet 6 also includes a stop 9 opposite the second small side 3b of the permanent magnet 1.

[0149] In order to allow the deformation of the deformable tabs 7, the rotor comprises sheets provided with deformable tabs 7, as well as sheets without deformable tabs 7, as illustrated in figures 5 and 6. The different sheets are arranged alternately, in order to allow the deformation of the deformable tabs 7 outside the plane of the sheet.

[0150] Of course, the invention is not limited to the exemplary embodiments which have just been described.

[0151] The rotor mass 33 may have other arrangements of the housings 4 intended to receive the magnets, within the rotor mass.

[0152] The housings 4 and the magnets 1 may have other geometric shapes. The housings may each extend along a longitudinal axis which may be straight or curved.

[0153] In the illustrated embodiments, all the rotor mass laminations have cutouts and tabs within the meaning of the invention. All the rotor mass laminations may be identical to each other.

[0154] Alternatively, the rotor could also comprise sheets without cutouts and tabs, these being in particular arranged in the middle of the rotor mass, between two sets of sheets provided with cutouts and tabs within the meaning of the invention.

Claims

Demands 1. Rotor (30) of a rotating electrical machine, comprising: - at least one permanent magnet (1) having in cross-section, perpendicular to an axis of rotation of the rotor, at least one long side (2a) and at least one short side (3a), - a rotor mass (33) comprising stacked laminations, the rotor mass (33) comprising at least one housing (4) for receiving the permanent magnet (1), the housing (4) being delimited by at least one large face (5a) opposite one long side (2a) of the permanent magnet (1), at least one lamination (6) comprising at least two cutouts (10) providing between them at least one tab (12) connecting to said large face (5a) of the housing (4) and extending into the housing (4), in particular towards the air gap, the tab(s) not being deformable, not deforming outside the plane of the lamination when the permanent magnets are inserted into the rotor mass, the lamination (6) comprising one or more punching holes (15) provided in the tab(s) (12) and allowing the permanent magnet (1) to be held against an opposite face (6b) of the housing (4), punching being a deformation of the sheet metal, which is convex towards the inside of the housing, being non-through.

2. Rotor according to the preceding claim, the leg or legs (12) being symmetrical in shape with respect to an axis of symmetry, in particular an axis of elongation of the leg.

3. Rotor according to any one of the preceding claims, the cutout(s) (10) having a general V-shape, with a rounded bottom.

4. Rotor according to any one of the preceding claims, the leg(s) (12) having a flat at their free end.

5. Rotor according to any one of the preceding claims, the leg(s) (12) being positioned at the center of a face (5a) of the corresponding housing, in particular at the center of a large face of the corresponding housing.

6. Rotor according to any one of the preceding claims, at least one permanent magnet having a groove (20), in particular along its entire length, intended to receive one or more tabs (12) of sheet metal of the rotor mass.

7. Rotor according to any one of the preceding claims, the rotor comprising permanent magnets (1) being arranged in one or more rows, in particular in U or V.

8. Rotor according to any one of the preceding claims, the rotor comprising permanent magnets (1) arranged to form rotor poles, the cutouts and / or punching of a rotor pole being arranged symmetrically with respect to each other.

9. Rotor according to any one of the preceding claims, at least one sheet (6) comprising at least one deformable tab (7).

10. Rotor according to the preceding claim, the permanent magnet (1) having in cross-section a first small side (3a) and a second small side (3b), opposite the first, the tab (7) being configured to press against the first small side (3a) of the permanent magnet (1), at least one sheet having at least one stop (9) opposite the second small side (3b) of the permanent magnet (1).

11. Rotor according to any one of the preceding claims, also comprising sheets (6) without cutouts and tabs.

12. Rotor according to any one of the preceding claims, the housing (4) being delimited by at least one large face (5a) opposite one large side (2a) of the permanent magnet (1), at least one sheet (6) having at least one tab (7) connecting to one large face (5a) of the housing (4) and extending into the housing (4), in particular in the direction of the air gap, the tab(s) (7) allowing the permanent magnet (1) to be held against an opposite face (5b) of the housing (4).

13. Rotating electrical machine, comprising a stator and a rotor (30) as defined according to any one of the preceding claims.

14. A method for manufacturing a rotor for a rotating electrical machine, in particular according to any one of the preceding claims, comprising the following steps: (a) provide a rotor mass (33) of the rotor comprising housings (4) in which extend one or more tabs (12) each formed between two cutouts (10), (b) insert permanent magnets (1) into the rotor mass housings of the rotor, the tabs (12) not undergoing deformation during this insertion, and (c) make one or more punching holes (15) in the leg(s) (12) so as to retain the permanent magnet (1) against an opposite face (5b) of the housing (4), the punching being a deformation of the sheet metal, which is convex towards the inside of the housing, being non-through.

Images